The invention covers a position determining arrangement having an inductive sensor.
In such sensors, the inductivity of a coil will be changed by moving the position of an iron core. By means of electonics, this change will be measured and converted into a linear motion measurement.
To date, it has been customary to use a coil to determine the frequency of an oscillator circuit as shown in German Patent No. DE-OS 20 46 336. Whenever the inductivity is changed, the oscillator circuit will change. The resulting change in frequency is then analyzed and transformed into a corresponding linear motion signal.
The disadvantage of this solution is the dependence of active oscillator components on temperature, whereby the measured value becomes inaccurate, especially when temperature fluctuations are large. Furthermore, the relationship between frequency and inductivity, or the path traveled by the iron core with f=1/2.pi..sqroot.L.times.C is not linear, whereby a corrective switching may be necessary.